<template>
  <div :class="{ hidden: hidden }" class="pagination-container">
    <el-pagination :background="background" :current-page.sync="currentPage" :page-size.sync="pageSize" :layout="layout"
      :page-sizes="pageSizes" :pager-count="pagerCount" :total="total" v-bind="$attrs" @size-change="handleSizeChange"
      @current-change="handleCurrentChange" />
  </div>
</template>

<script>
export default {
  name: 'Pagination',
  props: {
    total: {
      required: true,
      type: Number
    },
    page: {
      type: Number,
      default: 1
    },
    limit: {
      type: Number,
      default: 20
    },
    pageSizes: {
      type: Array,
      default () {
        return [5, 10, 20, 30, 50]
      }
    },
    // 移动端页码按钮的数量端默认值5
    pagerCount: {
      type: Number,
      default: document.body.clientWidth < 992 ? 5 : 7
    },
    layout: {
      type: String,
      default: 'total, sizes, prev, pager, next, jumper'
    },
    background: {
      type: Boolean,
      default: true
    },
    autoScroll: {
      type: Boolean,
      default: true
    },
    hidden: {
      type: Boolean,
      default: false
    }
  },
  data() {
    return {
      state: true
    }
  },
  computed: {
    currentPage: {
      get () {
        return this.page
      },
      set (val) {
        this.$emit('update:page', val)
      }
    },
    pageSize: {
      get () {
        return this.limit
      },
      set (val) {
        this.$emit('update:limit', val)
      }
    }
  },
  methods: {
    handleSizeChange (val) {
      const pageMax = Math.ceil(this.total / val) // 先手动计算要跳转的最大页数
      if (this.page > pageMax) { // 判断当前页是否大于最大页数, 如果是就返回最大页数
        this.state = false // 再设置一个状态值, 当state为false时, handleCurrentChange事件将直接return, 这样就不会出现调用两次接口的情况
        this.$emit('pagination', { page: pageMax, limit: val })
      } else {
        this.$emit('pagination', { page: this.currentPage, limit: val })
      }
      // if (this.autoScroll) {
      //   scrollTo(0, 800)
      // }
    },
    handleCurrentChange (val) {
      if (this.state === false) {
        this.state = true
        return
      }
      this.$emit('pagination', { page: val, limit: this.pageSize })
      // if (this.autoScroll) {
      //   scrollTo(0, 800)
      // }
    }
  }
}
</script>

<style scoped>
.pagination-container {
  background: #fff;
  padding: 15px 16px;
}

.pagination-container.hidden {
  display: none;
}
</style>
